Just wanted to give a shout out to PJ Library for anyone (willing to claim that they are) Jewish. There is a free service where they send a free book a month. I'm ethnically Jewish but not religious at all. Don't support the current Isreali regime at all. Etc. And I love the books. They are not religious books. My kids favorite one is about a penguin and an elephant and going to grandma's house for dinner.

What I remember reading to my kids aged 5-10

The Hobbit

The Fellowship of the Ring (more for me but they liked to snuggle up and fall asleep to it)

Harry Potter 1-5 (the hardback versions with lots of pictures)

Eric the Viking - Terry Jones - a personal fav of mine

Various compendiums of Greek and Norse Myths

Dr Seuss books

What do people do all day - Richard Scarry

My son started reading the Beastquest books very early by himself and was happy to read independently from there. After that at around 8 he started reading diary of a wimpy kid and the 13 storey treehouse type books.

When my kids were that age I read several of the Edge Chronicles. https://en.wikipedia.org/wiki/The_Edge_Chronicles

My childhood favorite is the Dragonlance Twins trilogy. https://en.wikipedia.org/wiki/Dragonlance_Legends

Only have a 1-year-old, but I can imagine reading Narnia to them when they're a bit older. Those books are amazing! Currently mostly reading Miffy (a classic in the Netherlands) and Peppa Pig ;)

Winnie the Pooh is my daughter's favorite

It was three decades ago, but I read The Phantom Tollbooth and The Hobbit to my daughter around that age.

Greek Mythology (PG-3 version), God bless Sir Fry for his books. They are amazing.

Fairy tales I make inspired by some famous tale, but using local geography (mountains, woods, local trees, etc.).

Kid loves both. While early on he was just falling asleep, these days I have to stop because between his excitement and the three million questions the narrative might take 1.5 hours...

Calvin & Hobbes, Big Nate, Wimpy Kid. Calvin and Hobbes literaly got him to make a clone machine and got me to play Calvinball with him. lol

No kids, but I'm listening to His Dark Materials currently, and would recommend it to every parent. 5 and 6 might be a bit young for it, I would compare it to the third or fourth Harry Potter books in terms of maturity. Got great themes and messages too.

Cars and Trucks and Things That Go is a timeless classic, with a fair bit of real world info about how roads are consrructed and paved, and has a TON of re-readability.

How Did That Get in My Lunchbox? is an age-appropriate look at where food comes from and the effort it takes from farm to lunchbox. Fantastic for giving a glimpse of how the world works.

Human Body Theater is maybe a bit advanced for 5-6, but got a lot of mileage at our house. Think 7th grade human biology in a cute comic book form - depends on the kids, but ours were engrossed.

The Narnia books by CS Lewis are very good IMHO. But you might want to wait a year or two.

Wizard of Oz to my 7 yo daughter and 4 yo son. They are just captured by the world and characters without ever seeing anything related to the movie.

Non-fiction: The Sound of a Wild Snail Eating

This prompted me to lay belly-down and listen to the snik-snik-snik sound of a slug munching grass.

Skulduggery Pleasant currently.

Read Harry Potter obviously. And His Dark Materials.

Give 'Rosie Revere, Engineer' a look

The Very Hungry Caterpillar ∞

The Bravest Ever Bear.

The secret to writing a good childrens' book is writing something that an adult can read multiple times without going insane. The Bravest Ever Bear works by that metric.

By the way, note that His Dark Materials is atheist coded in the same way that Narnia is christian coded.

The Hobbit

We go to the library a few times a month and pick out new books. Our reading list is always changing. Buying new books is pretty expensive, as we don't read most books repeatedly for more than a week or two.

Frog & Toad series by Arnold Lobel is a favorite.